The invention relates generally to a light-transmissive material and methods of manufacture and more specifically to the use of such a material in a rear projection screen.
Light-transmissive materials which are suitable for rear projection screens typically sacrifice the vertical angle of view in order to optimize the horizontal angle of view and the gain of the screen. There exists a need to provide low cost light-transmissive materials in which the vertical angle of view and the horizontal angle of view may be optimized independently of one another.
The present invention addresses these needs.
A light-transmissive material has been developed which provides increased light-transmissive properties. The light-transmissive material of the invention uses two distinct particles to provide the increased light-transmissive properties. When used in a rear projection screen, the light-transmissive material of the present invention exhibits high gain, high contrast, low scintillation, and optimal horizontal and vertical angles of view.
The light-transmissive material generally includes a matrix and a plurality of ellipsoidal dispersive particles and a plurality of spheroidal dispersive particles disposed within the matrix. The ellipsoidal particles typically have their major axes oriented substantially orthogonal to the direction at which the material will be viewed. The two distinct particle types each independently contributes to the overall performance of the material.
In another embodiment of the invention, the light-transmissive material includes a light channeling contrast enhancement layer. The light channeling contrast enhancement layer permits viewing under high ambient light conditions.
The light-transmissive material can be economically manufactured using methods of the invention. In a broadest form of the method, an appropriate matrix material, a first substantially spheroidal dispersion material and a second dispersion material are combined to form a mixture. The second dispersion material is capable of being deformed into ellipsoidal dispersive particles at an appropriate processing temperature. Subsequent to mixing, a sheet of material typically is formed from the mixture, heated to the processing temperature and stretched along an axis to produce the light-transmissive material of the invention. By stretching the material, the second dispersive material is deformed into ellipsoidal particles while the first dispersive material remains substantially spheroidal, thereby providing the two particle types embedded in the matrix for enhanced performance.
The invention will be understood further upon consideration of the following drawings, description and claims.